Seating tool



Mwah 10, 1931.

l. 1 WADE ET AL SEATING TOOL 2 sheets-sheet 1 Filed May 18, 1929 Marchl0, 1931.v 1. L. WADE E 'rjAL 1,795,323

SEATING. TOOL Filed may. 18, 1929 2 sheets-sheet 2 w- "if,

bye/22%@ ffm/f? [,.Zdzda- Patented Mar. 10, 1931 caire STATE-s 4Pararrrtrice IBvINe L. WADE, or OAK BABK, AND COLIN B. ROBERTSON, OF BLUEISLAND, ILLINOIS SEATING TOOL VApplication filed May 1K8, 1929. SerialNo. 364,230.

rllhis invention relates to a tool for resurfacing hand hole seats andthe like, and has for its principal obyect the production of a portabletool adapted for resurfacing the4 hand hole seat of a wat-er tubeboiler.

In high pressure water tube boilers, the

redressed to remove nicks or other irregularities that may be placed invthe seat during the operation of' cleaning theV boiler.

The preferred embodiment of our invention consists of a light yet sturdyportable dressing machine cOnsisting'o-f a stationary base adapted to beattached to theoutside of the header and a'tool head adapted forattaching to that base and containing atool holder'whichis projectedthrough the hand hole cover to bring the cutting edge of the tool intoengagement with the surface that is to Vbe reseated. The kpower foroperating the-cutting tool is applied manually to the toolhead,V andthat head contains also an adjustment for regulating the. depth of cutso that the surface can he' quickly and economically reconditioned.

Obviously, the method of reseating the inside faces of the hand hole ofa header thus enumerated is capable of being more quickly accomplishedand, therefore, cheaper than the scraping and filing methods which havebeen used heretofore. i

To acquaint those skilled in the art with the teachings of ourinvention, we have shown a preferred embodiment of it by way of eX-ample, in the accompanying drawings in which:

Figure l shows the rosea-ting tool attached to the header of a boiler,

Figure 2 is afrear or boiler side view of the tool shown in Figure 17Figure 3 is a detailed view of the tool post and carriage therefor,

Figure l is a cross-sectional view of the tool bed attached to a boilerheader with the locating plate or jig in place,

Figure 5 is a cut-away view of a boiler header showing the hand hole capin place,

` Figure 6 isa plan view of the locating plate, and

Figure 7 is a cross-sectional view of Figure (3 taken-along the line 77.

Referring to Figure 5 in more detail it will be seen that the header 85Vcomprises a boxlike structure easily made of either cast iron orwrought steel. The opening 84 is provided to receive one of the watertubes of the boiler. Directly opposite this hole in the front faceY 15of the header is the hand hole 16 which is closed by the hand hole cover8() which bears against the inside vsurface of the front plate 15 of theheader. It is this bearing surface that must be main-tained smooth andfree from dents if thehand hole cover 80 is to seal the opening againstthe boiler pressure.

The hand hole cover 80 is held in place by the stirrup 81 through whichpasses the bolt 8:2, that bolt Vbeing permanently attached to the handhole cover 80. A nut 83 bears against the outside face of the stirrup 81and locks the cover in place It will be noted that the seat of thestirrup 81 bears against the surface of the front face 15 of the headerat points directly opposite to the bearing points of the cover 80. Bythis arrangement the tension put on the bol-t82 by the nut 83 does notadd stresses to the walls 15 of the header Sorbut rather compressesthose walls beneath the seat of the stirrup 81 and the bearing surface.of the cover 80.

As will be seen on pages 50 vand 51 of the book Steam and Generation andUse published by the Babcock and l/Vilcox Company of New York andcopyrighted 1920 bv that company, the headers are of serpentine orsuiuous form. That is, the centers-of adiacent boiler tube Openings andcorrespondinghand holes in ti e header are staggered with respect toeach other. ln effect there are two lilies of these openings, andadjacent openings are placed in opposite lines. By this arrangement thewater tubes of the boiler are staggered thereby allor-ding the gases inthe combustion chamber better access to them.

1n Figure -1 we show the tool bed 1 attached to a` header of the typeshown in the above referred to book. The hand holes 16, 17 and 18 areshown to be hand holes in one of the lines ou the header, that is, thereis a hand hole disposed between the holes 16 and 17 but in the otherline on the header and also there is another hand hole disposed betweenholes 17 and 18 it likewise being in the other line on the header.

The tool led 1 comprises a piece ot channel iron ot suitable dimensionsand length to span three hand holes in any one line on the boilerheader. A channel iron chosen tor this purpose because ot .its greaterresistan to bending ior a given weight of metal. The channel comprisesthe web section l and flanges 2 and 3 as will be seen in Figures 1, 2and 1. At opposite ends et the web, section 4, we have cut slots 5 and 6through which the bolts 12 and 20 respectively are projected to lock thetool bed onto the tace ot the header. These bolts are provided withstirrups such as 14, and 19 whicn are similar to the stirrups employedto loch the hand hole covers in place on the header. However, thestirrups 14 and 19 are sonrewhat longer than the hand hole coverstirrups, and bear against the inside surface oi' the header walloutside oi the machined seat against which the hand hole cover bear Thisarrangement permits lodging tue bolt 12 tor example and the hand hole 16which has been reseated without damaging the seat, since the stirrnpbears against the metal dispos d beyond the seated suriace.

'the tool bed is also provided with adp" ting' set screws 10 and 11which are threaded through openings 7. 8 and Sl in the web o'l' thechannel. l thes rllhe ends oi' screws bear against the. outside face oi"the header wall 15, and by proper adjI 'ent ot these set scrtuvs the web4 of the can be aligned parallel tcthe walls oi the header.

The tool hed 1 is provided with a rectangular opening si centrallylocated in the web portion #1:, through which opening the cutting tooland the locating tool are projected into contact with the boiler header.Obviously` this opening il need not be 1nire nor need it be of the exactdimensions shown since its only purpose is to permit projection oit' thetools through the bed imo engagement with the boiler header.

By drawing up on the nuts 1?) and 21, attached to the bolts 12 and 2Orespectively` the tool bed can be s-:ecurely locked to the header awayfrom which it is held by the set screws 10 and 11.

lilith the tool bed so located parallel to the walls ot the header thelocating plate or jig 70, snown in detail in Figures 5 and 7, isattached to the tool bed 1 by the four bolts 28, 29, 3() and 31 whichproject through the holes 77 located in the corners of the plate 70. ltwill be noted that the diameter of these holes 77 considerably greaterthan the diameter ot the screws 28 to 31 inclusive, and it will beobvious that by this arrangement the lateral movement of the plate onthe mounting bed 1 is possible.

if he locating plate 7 0 co uns in addition the central web 71 uponwhich is .fastened the bushing 72, that bushing being held by the screws73 which are threaded into the web 71. A. square opening extends throughthe bushing 72 and the web section 71., and a square shaft 75 projectsthrough this opening. A cam 7d is attached to the end of this shaft 75by the bolt 76, that cam being oval shaped and designed to snugly litinto the hand here in the boiler leader.

After the locating plate70 has been fastened onto the tool bed 1 by thebolts 28 to 31 inclusive, adjusting nuts 26, 27, 22, 23', 2l and 25 areturned as is necessary to move the plate 70 so that the cam 742 slidesinto and out of the hand hole 17 in the header without binding.

Since the cani is mounted on a square shaft that is joui-nailed in asrpiare hole on the locating plate 70, the entire assembly must berotated in order to bring the cam into proper alignment with the handhole. This rotation is a :complished by variation in the adjustment etthe locating screws 22 to 27 inclusive, which screws are also adjustedto move the locating plate laterally in both directions on the tool bed1.

After the locating plate has been properly positioned, clamping screws2S, 29, 3() and 3l are removed and the plate taken ott ot' the mountingbed 1. lf desired, the locating screws 22 to 27 inclusive may beprovided with lock nuts to insure that they will not be moved after thelocating plate has been properly set, however, we have not found that itis necessary to add lock nuts to the screws.

The cutting head, shown in detail in Figures 1 to 2l, is mounted on abase 4l() which is of identically the same size as the locating plate70, and if the cutting head plate l0 is Yfastened on to the toolmounting' bed 1 without altering' the adjustment ot the locating screws22 to 27 inclusive, that head will be properly located in four ot' the.directions with respect to the header. 'l`he other directions, the inand out movement of the cutter blade with respect to the header, areadjusted by an adjusting collar on the cutting head.

By reference to Figure 1, 2 and 3 it will be seen that the cutting'headcomprises the mounting plate l0 in the center of which is attachedthe threaded collar 41.

The adjusting collar 42 is threaded to engage the collar 4.1, and alsothreaded to engage the bushing 43 which is co'ncentrically locatedwithin the collar 4l and. lodged against rotation by the key 44 whichfits into the keyway 46 in the collar 41 and is held therein by thescrew 45. Y 'y ,l Y

In the preferred embodiment of our invention the threads on the collar41 are right hand threads and the V'threads on the bushing 43 are lefthand threads so that a rotation of the collar 42 movesY the bushing 43longitudinally a distance equal to the sum of the pitch of thethreads onthe collar and bushing. Obviously, if desired, the threads on the collar41 may be made right hand threads and the threads on the collar 43 mayalso rbe right hand threads of a different pitch so that a movementofthe collar 42 through one complete revolution will move the bushing 43with respect to the collar and mounting plate 40 a distance equal to thedifference in the pitches of the two right hand screw threads. This, ofcourse, would give a much finer adjustment particularly if thedifference between the pitches of the threads on the collar 41 and ontlije bushing 43 is slight, however we have found that it is notnecessary to have a micrometer adjustment of the cutting tool and sincethe lateral adjustment of this tool is more rapidly accomplished by aleft and right hand thread as shown, we have employed that arrangementin the preferred embodimentof our invention.

rlhe cutting tool 55 is held in the tool stock by the set screw 56.Yr'lhe tool stock 54 is attached to the plate 53 which is dove-tailedinto the head stock 52, as shown at 68 inthe Figures 1 and 3. f he tool55 is preferably made of tool steel of suitable size, and is ground witha cutting edge as shown. This cutting edge shears the metal from theseat without chattering and in addition the pressure of the metal sosheared exerts a force on the tool substantially along its axis. Thisforce cooperates with the tension of spring 57 to keep the roller 58firmly sea-ted on the cam 47, so that the tool is accurately guided overits path by the cam. f

lt will be noted in Figure 3 that the tool post 54 is off-set from thecenter of the plate 53. and that the tool point coincides with the axisof the roller 58. This adjustment insures that the seat will be cut.accurately as the contourof the cam, since the extreme point of the toolaccurately coincides with the a-Xis of the roller which moves around thecam as the tool is turned.

The tool 55 as shown in the preferred embodiment of our invention, isdesigned to cut` a'at seat. Obviously the invention is not limited tothis type-of tool and by suitable design of the tool any preferred formof seat can be cut. VSince the tool moves 1n a concentric path aroundthe seat, the tool may be shaped to cut a groove on aledge 1n the seatif desired. The particular shape of the tool is not of the essence ofour invention and we are not, therefore, to be limited by the shapeshown.

A plate 69 is held in the head stock by the screw 69, to1adjust the toolpost plate 53 therein. x

The head stock 52 is mounted -upon the shaftV which fits snugly butrotatably in the bushing 43. Preferably bronze bearings 48 and 49 arefitted intov thebushing 43 to afford a proper bearing for the shaft 50.

The shaftv50 is locked in the bushingassembly by the lock nuts 58 whichare threaded onto the shaft and brought to bear against the bushing 48.Y

On the boiler end. of the bushing 43 is located a round shaped head .43.steel cam 47 is attached to the plate 43 by screws or bolts, thatl camserv-ing to guide the cutting tool around the periphery of the handhole. Within the cam47 is a circular opening 51 located concentricallywith. the axis of the shaft 5() into which the circular part 51 oftliehead stoclr'52 fits and rotates. rlhe facef51 of this circularportion 51 bears against the end of the bushing 49 and cooperates `withthe nuts 58 to lock the shaft therein. A m Y Attached to a projection 53of the tool stock bed 53 is aroller 58 which bears against I the'cam 47to guide the tool 5.5. This roller is held onto the member 53 by ashoulder screw 5.9 threaded therein to permit free rotation of theroller 58 about the screw as an axis: v 1

Within the dove-tail portion of the head stock 52 isa generallyrectangular cavity A52 in which is -disposed a 'spring 5.7, one 'end ofwhich is. fixed with respect to the head stock 52 by theclamp 64 whichisv attached to the head .stock by the screw 65. The opposite end of thespring 57 .is held Vdefinitely with respect to the tool post base 53 bythe bracket 66vv which is `held thereon by the screw 67. The spring 57is tensioned so that it tends to movethe tool post 54 to the left, asseen in Figure 1, thereby insuring that the roller 58 will securely bearagainst the-cam 47. When the cutting head is being placed on the toolbed 1, the adjusting collar 42 is rotated so that the cutting tool isdisposed back of and away from the face 15 ofthe header. After thecutting head has been secured by tightening the bolts 28 to 31 inclusivetheV collar 42-is readjusted by aA Spanner wrench, not shown, which isinserted in the holes to turn the cutterin the proper direction to bringthe cutting` head into engagement with the back surface of the headerwall. outer face of the colla-r 42 is lrnurled, as shown at 9.1, so thatin so far as possible the adjustment may be made by hand withoutIth'evuse of a lspanner wrench since that method affords a more rapidadjustment of the cut- A hardened The v`3 lil) ter. However, the spannerwill have to be used for the fina-l adjustment when the cutter 55 isbrought intocutting relation with the plate 15. v

Ve have found that it is not' often neces- `:zary to take a heavy cutoff of these plates to resurface the seats, as in most instances a cutof from six to eight thousandths of an inch is all that it is necessaryto take. The cutting may be accomplished by attaching a wrench or handwheel, neither shown, to the square portion 59 of the shaft 50, andthereby rotating that shaft in the proper direction to cause the tool toshave the metal off of the plate 15. As the shaft 50 is rotated, theroller 58 follows the contour of the cam 47. Since the cam 47 is shapedexactly as the periphery of the hand hole 17, the cutter will follow theperiphery of the hand hole exactly and reiinish the seat around thatperiphery. usually these seats are approximately a. quarter of an inchwide, and the cutter 55 is so shaped that it will surface the entireseat at one eut.

Thehandholes of various makes of boilers vary both in shape and size,however, all of a `generally oval shape. Obviously, by suitablydesigning the cam f7 the cutter disclosed .in Figure l can be made toresurface the seat of any hand hole within the limits of lateralmovement made' possible by .the tool post slide 53 and the head 52.lVith the head proportioned as vshownythe machine is capable ofsurfacing a hand hole having approximately four inches as its maximumdimension, that size beingl sufficient for the majority of boilers nowin common use.

Gbviously the head stoel( 52 and tool post slide 53 can be suitablydesigned for a larger f lateral movement and the Cam 47 can becorrespondingly designed so that larger hand holes. or even man holes,can be resurfaced in this manner if desired.

After the seat of hand hole 17 has been resurfaced the cutting head isremoved from the tool bed 1 by removing the screws 28 to 31 inclusiveand the bed is then removed from the header by removing bolts 12 and 20,and the assembly can be setup on adjacent hand holes if desired. Sincethe bearing seatof the stirrups 141 and 19 do not bear against theportion of the header wall 15 that has been seated by the tool, eitherof the stir-rups can be inserted in the hole 17 without damage to theseat that has just grease is forced into the channel 61 through this cupand entersthe bea-ring surface of the shaft through the duet 62 andlubricates the shaft to, insure that it will rotate freely in thebushings.

From the foregoing description, it will be apparent that We have devisedan improved tool for resurfacing the hand hole seats of the headers of awater tube boiler, or for other similar cutting operations, a tool thatpermits a performanceof this operation at a greater speed than has beenpossible heretofore with a consequent reduction in the cost of theoperation.

lVhile we have chosen to show a preferred embodiment of our invent-ion,we have done so by way of example only, as we are aware that there aremany modifications and adaptations which can be made by one skilled inthe art without departing from the teachings of the invention.

Having thus complied with the statutes and shown and described apreferred embodiment of our invention, what we consider new and desireto have protected by Letters Patent is pointed out in the appendedclaims.

lVhat is claimed is:

1. ln a hand hole cap seating device, the combination of a bed plate,means for attaching said plate to a body on which a cap is to be seated,said means being adjustable to align said plate parallel to said body, atool head removably fastened 4to said bed and adjustable thereon, andmeans on said tool head for moving a cutter over a noncircular path in aplane parallel to said bed plate.

2. vln a hand hole cap reseating device, the combination of a bed plate,means for attaching said plate to a body on which a cap is to be seated,said means being adjustable to align said plate parallel to said body, atool head removably fastened to said bed and adjustable thereon, meanson said tool head for moving a cutter over a non-circular path in aplane parallel to said bed plateAy and means for adjusting the distancebetween the plane, in which said cutter moves, and said bed plate.

3. In a hand hole cap seating device, the combination of a bed plate,means for attaehing said plate to and aligning it parallel to a body onwhich a cap is to be seated, a tool head removably fastened to said bedand adjustable thereon, a shaft on said tool head, a cutter on saidshaft, a cam on said tool head for guiding said cutter' over a pathdetermined by the shape and position of said cam as the shaft isrotated, and means for adjusting the distance between said cutter' andbed plate.

4. In a hand hole cap seating devire, the combination of a bed plate,means for attaching said plate to and aligning it parallel to a body onwhich a cap is to be seated, a

sie

messer tool head removably fastened to said bed and adjustable thereon,a shaft on said tool head, a cutter on said shaft, a cam on'said toolhead for guiding said cutter over a pathde-V said. shaft foradjustingthe distance between said cutter and said bed plate.

j 5. ln combination with na tool for resurfacing the hand hole'rcapseats ofi a boiler, a bed plate for mounting` said tool on the boiler',

vstud screws in said plate for adjustably holding it awayfrom thesurface of the boiler, bolts for holding the bed on the boiler, and

:stirrups .on said bolts, said stirrups projectA Ying through the handholes of said boiler and bearing agalnstthe inside surface thereofV atpoints vb eyond the cap seats.

6. A toolfor reseati'ngn the hand hole cap seats ,ofa Water tube boilerWhich comprises the combination of, a tool bed plate, means for holdingit on the boiler, a tool mounted on said plate, a'cam associated withsaid tool and fixed-against rotation with respect to said plate, meansfor rotating saidrtool around the viperipheryof said cam and means foradjusting said vtool vatright angles to the planes of 'said cam and bedlplate to thereby regulate the depth of cut taken by the tool.

7. A hand hole cap re'seating tool compris ing, a bed plate, means forattaching said bed late on the header in Which the cap seat is to Eecut, a tool head mounted thereon, means for adjusting the position ofsaid head on said base, a tool carrier attached to said head, a camattached to said head in xed relation with respect thereto, a rollermounted on said carrier and engaging said cam, a shaft on said toolcarrier. projecting through saidliead, threads on said head, a collarcoo-perating With said threads to adjust the position of said tool headand tool carrier With respect to. said bed plate, a cutter mounted insaid carrier, means for rotating said shaft to thereby move said carrierand cutter over a path defined bysaid cam to cut the cap seat in saidheader.

8. In a hand holel cap seating tool, a shaft, means for attaching thetool to a header, means for locating the tool with the axis of the shaftcoinciding With the center of the cap opening, a cam concentric withsaid shaft, said cam being of the same shape as the cap opening, a crosshead on said shaft, a tool post slidably mounted on said cross head, aroller attached to said tool post, means for retaining said rolleragainst said cani to guide the tool post as the shaft is rotated, andmeans for rotating the shaft.

9. In a hand hole cap seating tool, a shaft, a tool post including meansfor holding a cutting tool,a tool post slide, a cam, means on said toolpost engaging said cam to guide the movement of said tool post in saidslide, means 1for attaching said seating tool on a header with the shaftlaxis coinciding with the center of the hand hole and with the peripheryof said'cam coinciding With the periphery of the hand hole, means foradjusting the tool post along the axisof said shaft of the header WallaroundA said hand hole.

10. In a tool for i'eseating hand hole caps of aboiler, a shaft, a camvconcentrically located around said shaft,a cutter mounted v on saidshaft, a roller associated with said cutter and ,engaging the cam toguide the cutter, a base plate, means forv mounting said shaft on saidplate in fixed relation thereto, said means including means for movingthe shaft cutter and camv longitudinally with respect 'to the baseplate, 'a bedv plate, means for mounting said' bed plate on a header,said means including means for locating the plane of the bed parallel tothe faceof theheader, means for mounting the base plate on the bedplate,=andmeans for adjusting the base on thebed to bring the axis ofsaid shaft into coincidence with the center of a hand hole in the headerto thereby locate the path of travel ofsaid cutter iii plane paralleltothe face of said header. y

1l. *A* tool-for reseatiiig hand hole caps of a boiler which comprises,a channel bed plate having slots disposed at its opposite ends in itsWeb, boltsprojecting through said slots, stirrup heads ony said boltsfor .engaging the and means for rotating the shaft to cause ,said YVtool post to followv the periphery of theshaft and the cutting tool tosmooth the inside face inside surface of the yheader containing the handholes, set screws threaded through the -Webof said channel intoengagement with ment of the base on the bed, a shaft ecarried on saidtool heads, means Aon said bed 'for adjusting vsaid base laterallytofposition said shaft so that its axis coincides With the center .lineof said hand hole, a rcutter mounted on said shaft and means formovingsaid cutter around the periphery of said hand hole and in a planeparallel to that of the bed plate as said shaft is rotated. f l

l2. A tool for reseating hand hole caps of a boiler which comprises, achannel bed plate having slots disposed at its opposi-teends .in itsweb, bolts projecting through saidslots,

stirrup heads Yon said bolts Afor ,engagingYtheV ,inside surface of theheader. con-taiifiing the hand holes, set screws threaded through theWeb V.of said channel into engagement with the outside face oftheheader, said screws being adjusted to position said bed plate parallelWith the header, .a Vtool head having a iis base, bolts passing throughholes in said base to attach it to said bed plate, said holes beinglarge enough to permit lateral adjustmentof the base on the bed, a shaftcarried on said tool head, means on said bed for adjusting. said baselaterally to position said shaft so that its axis coincides with thecenter line Y of said hand hole, a cutter mounted n said shaft, andmeans on said tool head for adjusting` the distance between the plane inwhich the tool travels and the plane of the bed plate.

13. In a tool for reseating hand hole caps of a boiler, a rectangularbase plate, a thread .y ed collar centrally located on said base, a

bushing disposed within said collar and extending beyond it and saidbase, a keyway on the inside face of said collar, a key on said bushingfitted in said keyway to prevent rotation ef the bushing in the collar,a feed nut engaging said collar threads on said bushingV to move saidbushing in and out with respect to said base, a cam secured to thatportion of the bushing extending beyond f said base, a shaft extendingthroughl said bushing, the axis of said shaft passing through the centerof said cam, a circular recess in said cam concentric therewith, ashoulder on said shaft fitted into said recess, threads on said shaft,lock nuts threaded thereon and engaging the opposite end of said bushingto lock said shaft therein, a tool post mounted on said shaft, a rollermounted on the tool post and engaging the cam to guide the movement ofthe tool post as said shaft is rotated, a squared shank on said shaft onwhich a tool for rotating the shaft maybe placed, a bed plate on whichsaid base is mounted, means on said bed plate for attaching it into aheader of a boiler and for aligning it parallel thereto, and means onsaid bed plate for moving said base laterally thereon to align the axisof shaft with the center of the hand hole to be reseated.

14. The combination of a tool base, a tool head mounted on said base androtatable thereabout, said head being adjustable with respect to saidbase along the axis of said rotation and also at right angles to saidaxis, and means on said tools head for moving a cutter over anon-circular path in a plane parallel to said base.

15. The combination of a tool base, a tool head mounted on said base androtatable thereabout, said head being adjustable on the base in theplane of the base, and means for adjusting the distance between theplane on which said cutter moves and said base.

16. The combination of a bed plate, a tool head removably fastened tosaid bed and adjustable thereon in the plane thereof, and means on saidtool head for moving a cutter over a non-circular path in a planeparallel to said bed plate. f

17. The combination of a bed plate, a tool head removably fastened tosaid bed and adjustable thereon in the plane thereof, means on said toolhead for moving a cutter over a non-circular path in a plane parallel tosaid bed plate, and means for adjusting the distance between the plane,in which said cutter moves, and said bed plate.

18. The combination of a bed plate, a tool head removably fastened tosaid bed and adjustable thereon in the plane thereof, a shaft on saidtool head, a cutter on said shaft, a cam on said tool head for guidingsaid cutter over a path determined by the shape and posi tion of saidcam as the shaft is rotated, and

means for adjusting the distance between' said cutter, and bed plate.

19. The combination of a` bed plate, a tool head removably fastened tosaid bed and adj ustable thereon in the plane thereof, a shaft on saidtool head, a cutter on said shaft, a cam on said tool head for guidingsaid cutter over a path determined by the shape and position of said camas the shaft is rotated, and means including a right hand thread on saidtool head and a left hand thread associated with said shaft foradjusting the distance between said cutter and said bed plate.

In witness whereof, we hereunto subscribe our names this 15th day ofMay, 1929.

IRVING L. WADE. COLIN B. ROBERTSON.

